Method and device for producing a metal component

Abstract

The invention relates to a method for producing a metal structural component, in particular a vehicle structural component, in which a steel part is hot formed and is hardened at least over sections by contact with a tool surface, in which the steel part is during the hardening cooled in at least two partial regions at different cooling rates, so that the partial regions after the hardening differ in their microstructure, wherein the cooling rates differing from one another are produced by sections of the tool surface corresponding to the partial regions of the steel part, which differ from one another as regards their thermal conductivities. The invention also relates to a further method for producing a metal structural component, as well as a tool and a batch furnace.

The invention claimed is: 
     
       1. A method for producing a metal structural component, for use as a vehicle structural component, comprising the steps of:
 forming a steel part; 
 hardening the steel part at least over sections by contact with a tool surface; and 
 wherein the step of hardening includes the step of cooling the steel part in at least two partial regions with cooling rates differing from one another, so that the at least two partial regions differ after the step of hardening as regards their microstructure and wherein the cooling rates differing from one another are produced by at least two sections of the tool surface, corresponding to the at least two partial regions of the steel part, that differ from one another in their thermal conductivities, wherein at least one of the at least two sections of the tool surface has been coated so as to provide a surface coating that reduces or increases the thermal conductivity. 
 
     
     
       2. The method according to  claim 1 , wherein the tool in the region of the at least two sections of the tool surface consists of different materials with different thermal conductivities. 
     
     
       3. The method according to  claim 1 , wherein the at least two sections consist of steels and/or ceramics. 
     
     
       4. The method according to  claim 1 , wherein the steel part is heated in a second furnace before tempering the steel part in a batch furnace. 
     
     
       5. The method according to  claim 1  wherein the steel part is hardened in a pressing tool. 
     
     
       6. The method according to  claim 4 , wherein the batch furnace comprises at least one region with a temperature gradient. 
     
     
       7. The method according to  claim 1 , wherein the steel part is one of directly or indirectly heat formed and/or press hardened. 
     
     
       8. The method according to  claim 1 , wherein at least one boundary between the at least two partial regions runs at least one of 1) transverse or inclined to a largest longitudinal dimension of the steel part and/or 2) runs in a non-linear manner. 
     
     
       9. The method according to  claim 1 , wherein a semi-finished product, comprising one of a tailored blank, a tailored-welded blank, a patchwork blank or a tailored-rolled blank, or a sheet bar cut to size, is used as the steel part. 
     
     
       10. The method according to  claim 1 , wherein a steel part of MBW 1500, MBW 1700 or MBW 1900, or a steel part of MBW 1500, MBW 1700 or MBW 1900 in combination with a microalloyed steel MHZ 340, or a steel part of MBW 1500, MBW 1700 or MBW 1900 in combination with a microalloyed steel MHZ 340, is used. 
     
     
       11. The method according to  claim 1 , wherein the steel part has at least one of an organic coating, comprising an anti-scale protection that is a solvent- or water-based, one-component, two-component or multicomponent anti-scale protection, and/or an inorganic coating, that is an aluminium-based or aluminium-silicone-based coating, comprising a hot dip aluminised coating and/or a zinc-based coating. 
     
     
       12. The method according to  claim 1 , further comprising:
 forming at least one of an A, B or C pillar, side wall, roof frame or longitudinal member in a vehicle from said metal structural part.